7,943 research outputs found

    U.S. and U.K. Interest Rates 1890 - 1934: New Evidence on Structural Breaks

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    This paper presents econometric evidence on whether the founding of the Federal Reserve in 1914 caused a structural change from level-stationarity to difference-stationarity in U.S. and U.K. short-term nominal interest rates. We develop new econometric tests that allow for parameter transitions to test for a break of this kind and undertake a grid search analysis of dates and speeds for the change. We find that U.S. nominal interest rates most likely evolved rapidly to difference-stationarity in June 1917. For the U.K. we fail to reject the null that U.K. interest rate series follow a difference stationary process over the entire period 1890-1934. Our analysis differs from previous research on this topic in that we take care to explore statistical uncertainty around parameter estimates, and incorporate higher order dynamics into our econometric analysis.

    Text‐analysis reveals taxonomic and geographic disparities in animal pollination literature

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    Ecological systematic reviews and meta‐analyses have significantly increased our understanding of global biodiversity decline. However, for some ecological groups, incomplete and biased datasets have hindered our ability to construct robust, predictive models. One such group consists of the animal pollinators. Approximately 88% of wild plant species are thought to be pollinated by animals, with an estimated annual value of $230–410 billion dollars. Here we apply text‐analysis to quantify the taxonomic and geographical distribution of the animal pollinator literature, both temporally and spatially. We show that the publication of pollinator literature increased rapidly in the 1980s and 1990s. Taxonomically, we show that the distribution of pollinator literature is concentrated in the honey bees (Apis) and bumble bees (Bombus), and geographically in North America and Europe. At least 25% of pollination‐related abstracts mention a species of honey bee and at least 20% a species of bumble bee, and approximately 46% of abstracts are focussed on either North America (32%) or Europe (14%). Although these results indicate strong taxonomic and geographic biases in the pollinator literature, a large number of studies outside North America and Europe do exist. We then discuss how text‐analysis could be used to shorten the literature search for ecological systematic reviews and meta‐analyses, and to address more applied questions related to pollinator biodiversity, such as the identification of likely interacting plant–pollinator pairs and the number of pollinating species

    A first-level track trigger architecture for super-CMS

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    We present an architectural concept for a first-level hardware track trigger for CMS at SLHC. The design of such a system is challenging. A primary constraint on implementation will be power consumption within the detector, in turn driven by the transmission bandwidth to offdetector electronics. We therefore emphasise the minimisation of the data flow through local filtering of track stubs on the detector. The architecture does not comprise a stand-alone track trigger, but uses muon and calorimeter trigger objects to seed track-matching within an integrated first-level system

    Gene identification for the cblD defect of vitamin B12 metabolism

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    Background Vitamin B12 (cobalamin) is an essential cofactor in several metabolic pathways. Intracellular conversion of cobalamin to its two coenzymes, adenosylcobalamin in mitochondria and methylcobalamin in the cytoplasm, is necessary for the homeostasis of methylmalonic acid and homocysteine. Nine defects of intracellular cobalamin metabolism have been defined by means of somatic complementation analysis. One of these defects, the cblD defect, can cause isolated methylmalonic aciduria, isolated homocystinuria, or both. Affected persons present with multisystem clinical abnormalities, including developmental, hematologic, neurologic, and metabolic findings. The gene responsible for the cblD defect has not been identified. Methods We studied seven patients with the cblD defect, and skin fibroblasts from each were investigated in cell culture. Microcell-mediated chromosome transfer and refined genetic mapping were used to localize the responsible gene. This gene was transfected into cblD fibroblasts to test for the rescue of adenosylcobalamin and methylcobalamin synthesis. Results The cblD gene was localized to human chromosome 2q23.2, and a candidate gene, designated MMADHC (methylmalonic aciduria, cblD type, and homocystinuria), was identified in this region. Transfection of wild-type MMADHC rescued the cellular phenotype, and the functional importance of mutant alleles was shown by means of transfection with mutant constructs. The predicted MMADHC protein has sequence homology with a bacterial ATP-binding cassette transporter and contains a putative cobalamin binding motif and a putative mitochondrial targeting sequence. Conclusions Mutations in a gene we designated MMADHC are responsible for the cblD defect in vitamin B12 metabolism. Various mutations are associated with each of the three biochemical phenotypes of the disorder

    Examining Student Identification With The Alumni Organization At A 4-Year Commuter Campus

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    Past research has identified several institutional and individual antecedents that lead to greater intent to support an organization. This paper takes an organizational identification approach in developing an Alumni Relationship Model (ARM) that can be used by universities to generate greater support for their Alumni services activities. This paper shows that by going beyond traditional organizational identification models and by introducing new variables, it is possible to broaden and enrich both practice and theory of organizational identification within a university setting

    Manipulating rumen microbiome and fermentation through interventions during early life: a review:Rumen manipulation in early life

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    The nutritional manipulations of the rumen microbiome to enhance productivity and health are rather limited by the resilience of the ecosystem once established in the mature rumen. Based on recent studies, it has been suggested that the microbial colonisation that occurs soon after birth opens a possibility of manipulation with potential to produce lasting effects into adult life. This paper presents the state-of-the-art in relation to early-life nutritional interventions by addressing three areas: the development of the rumen as an organ in regards to the nutrition of the new-born, the main factors that determine the microbial population that first colonizes and establishes in the rumen, and the key immunity players that contribute to shaping the commensal microbiota in the early stage of life to understand host-microbiome specificity. The development of the rumen epithelium and muscularization are differently affected by the nature of the diet and special care should be taken with regards to transition from liquid (milk) to solid feed. The rumen is quickly colonized by all type of microorganisms straight after birth and the colonization pattern may be influenced by several factors such as presence/absence of adult animals, the first solid diet provided, and the inclusion of compounds that prevent/facilitate the establishment of some microorganisms or the direct inoculation of specific strains. The results presented show how early-life events may be related to the microbial community structure and/or the rumen activity in the animals post-weaning. This would create differences in adaptive capacity due to different early life experiences and leads to the idea of microbial programming. However, many elements need to be further studied such as: the most sensitive window of time for interventions, the best means to test long term effectiveness, the role of key microbial groups and host-immune regulations
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